1. Field of the Invention
The present invention relates to portable timepieces such as wrist watches or pocket watches, stand clocks, and wall clocks.
2. Description of the Related Art
A case for accommodating an inner frame which supports a movement of a timepiece includes a glass which allows viewing a dial of the movement therethrough, and an edge member which supports the glass is fixed to a body of the case using a mounting member.
In the related art, there is a known wrist watch having an edge member configured to have a cover portion on an outer periphery of one end portion of a cylindrical portion and a female screw portion on an inner periphery of the other end portion of the cylindrical portion, and a mounting member provided with a plurality of grooves for rotational operation on an inner peripheral portion of a ring base and a male screw portion so as to bent from the inner peripheral portion at a right angle for achieving the fixation (for example, see JP-A-2007-171127 (Patent Document 1)).
The edge member of this wrist watch is provided in such a manner that the cylindrical portion thereof is fitted into a fitting hole formed by a front-side end portion of the body of the case and the cover portion is overlapped with an edge receiving surface formed by a front surface of the front-side end portion. The mounting member is provided in such a manner that the male screw portion thereof is screwed into the female screw portion of the edge member. Accordingly, the edge member is fixed to the body in a state of clamping the front-side end portion of the body between the ring base being in contact with an engaging surface formed by a back surface of the front-side end portion and the cover portion being in contact with the edge receiving surface.
FIG. 4B shows part of a wrist watch according to Patent Document 1. In the drawing, reference numeral 1 denotes a case, reference numeral 2 denotes a body, reference numeral 3 denotes a front side end portion, reference numeral 3a denotes an edge receiving surface, reference numeral 3b denotes an engaging surface, reference numeral 4 denotes a fitting hole, reference numeral 5 denotes an edge member, reference numeral 5a denotes a cylindrical portion, reference numeral 5b denotes a cover portion, reference numeral 5c denotes a female screw portion, reference numeral 6 denotes a mounting member, reference numeral 6a denotes a ring base, reference numeral 6b denotes a groove, reference numeral 6c denotes a male screw portion, reference numeral 7 denotes a glass, reference numeral 8 denotes an inner frame, reference numeral 9 denotes a movement, and reference numeral 10 denotes a dial, respectively. Also, reference numeral 5d denotes a receiving portion which is formed on the inner peripheral side of the cylindrical portion 5a and receiving a peripheral portion of the dial 10.
In the wrist watch in the related art, a screwing portion between the edge member 5 and the mounting member 6 is formed on the inner peripheral side of the cylindrical portion 5a of the edge member 5. Accordingly, a thickness W2 extending along the radial direction of the cylindrical portion 5a corresponds to a sum of a dimension B of the screwing portion where the female screw portion 5c and the male screw portion 6c mesh with each other, a hooking margin C of the dial 10 with respect to the receiving portion 5d, and a gap D between the dial 10 and the male screw portion 6c. Since the thickness W2 of the cylindrical portion 5a cannot be narrowed any more, a width W0 of the edge member 5 defined by an inner peripheral surface (parting surface) of the cylindrical portion 5a viewed through the glass 7 and an outer periphery of the cover portion 5b is widened caused by the thickness W2.
The timepiece having the edge member 5 being large in width is not loved in terms of design in many cases. In addition, the edge member 5 having a wide width constitutes a factor of increase in weight of the wrist watch and the mounting member 6 including the ring base 6a and the male screw portion 6c constitutes a factor of increasing the weight of the watch. Therefore, the configuration of the related art in which the edge member 5 is fixed to the body 2 as described above is disadvantageous in terms of reduction of the weight of the wrist watch.
In addition, the wrist watch of the related art is provided with the ring base 6a of the mounting member 6 between a distal end inside the body of the cylindrical portion 5a and the inner frame 8. In other words, the ring base 6a is disposed so as to be overlapped with the cylindrical portion 5a in the axial direction. Therefore, when a priority is given to the thickness of the wrist watch, it is necessary to provide an undercut portion shown by reference numeral 8d in FIG. 4B on the inner frame 8 to store the ring base 6a in the undercut portion 8d. Accordingly, the point to be machined on the mounting member 6 is increased, and hence high cost of production is resulted.